rice4eatingnotdrivin

so i know this is common on a ls1 and ls6 motors but im getting a ticking noise from the passenger side head... at first it wasnt so bad but every now and then it gets pretty loud.... im thinking i have a "dead" lifter.. what im wondering is can i use a thiner oil to try and free it up and do i have to pull the heads off to replace the lifters??? i am putting a cam in the car so the valve springs and pushrods are being replaced anyways... any information will be very helpful... thanks in advance